1. Field of the Invention
The present invention relates to a connector and fastener for Christmas light strings and more particularly to an improved connector and fastener which engages with any selected socket of another Christmas light string for attaching more light bulbs to the Christmas light string for decoration.
2. Background Art
The fastener for connectors and sockets of this invention used in Christmas light strings is similar to the socket and bulb snap fasteners for Christmas light strings disclosed in U.S. Pat. Nos. 4,943,899 and 4,970,632.
U.S. patent application Ser. No. 675,310 of Wu et al. (Wu is also one of the inventors of the present invention) discloses a connector for Christmas light strings and fasteners therefor.
In this prior art, in FIG. 17, the connector 1 comprises a wire holding portion 20 for receiving and holding wires 30, 32 therein and a socket-engaging portion 10 for engaging with a conventional socket 60 of a Christmas light string (not shown).
The socket-engaging portion 10 includes an annular hollow receiving portion 12, a first annular protrusion 14, and a second annular protrusion 18. The annular hollow receiving portion 12 has a compartment 122 therein and an opening 16 at one end thereof and a wire holding portion 20, which includes two half casings 20a and 20b, each having two slots 22 and 24 separated by a wall 26 formed therebetween. The two half casings 20a and 20b are made of insulating material and one edge 25 thereof is formed together such that the two half casings 20a and 20b are pivotable with respect to each other.
Additionally, an annular recess 29 is formed on an outer periphery of the wire holding portion 20, and an annular flange 19 is formed on an inner periphery of the receiving portion 12 of the socket-engaging portion 10, such that when the wire holding portion 20 is inserted into the compartment 122 of the receiving portion 12, the annular recess 29 engages with the annular flange 19 to securely retain the wire holding portion 20 in the socket-engaging portion 10.
FIG. 18 shows another prior art socket and fastener. A T-shaped tongue 230 of insulating material, having a shoulder 232, is formed in the vicinity of an upper margin of the connector 1. A V-shaped groove 234 is formed on a lower side of the T-shaped tongue 230 at an end opposite to the free end of the tongue 230 and extends transversely across the length of tongue 230. A flexible receiving means 220 of insulating material is formed relative to the T-shaped tongue 230 on an upper margin of a periphery of the socket 60. The receiving means 220 comprises two opposite, L-shaped protrusions 222 which together form a compartment 224 and a path 226 slightly narrower than the width of the T-shaped tongue 230.
When engaging the connector 1 and the socket 60, the T-shaped tongue 230 is first bent downward about the V-shaped groove 234, and then the T-shaped tongue 230 is snapped into the compartment 224 via the path 226 such that the shoulder 232 of the T-shaped tongue 230 abuts a lower surface of both protrusions 222, as shown in FIG. 18a.
But, this prior art has some drawbacks. The annular recess and corresponding annular protrusion structure is neither easy to be engaged for connection nor easy to disconnect when the connection has to be repeated again. There is also a problem that the T-shaped tongue may be broken at a V-shaped location in a bending operation.